In three experiments, we compared the effects of instructional arrangements that varied in: (a) teacher versus peer mediators, (b) methods used, (c) levels of student academic responding generated, and (d) content taught and tested. Instructional arrangements (i.e., tasks, structure, teacher position, teacher behavior) and students' levels of academic responding were measured by an observation system which served as an index of the independent variables. Students' accuracy on weekly spelling, arithmetic, and vocabulary tests and pre-and post-standardized achievement tests (Experiments 2 and 3 only) were the dependent variables. Results indicated that the classwide peer tutoring, compared to the teacher's procedure, produced more student academic responding and higher weekly test scores, regardless of treatment order or subject matter content (Experiment 1). The four lowest performing students in each class, in particular, benefited from peer tutoring, often performing as well as the other students. These findings were replicated in Experiments 2 and 3 wherein content taught/tested was also manipulated. Standardized test score gains were higher in those areas in which peer tutoring was used longest. Issues related to the functional analysis of instruction and achievement gain are discussed.DESCRIPTORS: academic behavior, peer tutoring, classroom, elementary studentsOnly within the last 5 years have standardized achievement outcomes been causally attributed to teaching (Becker, 1977(Becker, , 1978Becker & Gersten, 1982;Brophy, 1979). Investigations of teaching practices that produce academic gains are beginning to yield exciting information on how to arrange lessons, how these arrangements affect student behavior, and in the long term, how they

We conducted a large-scale field replication study of classwide peer tutoring applied to spelling instruction (Greenwood, Delquadri, & Hall, 1984). Two hundred and eleven inner-city students in four schools participated during their first- and second-grade school years. The effects of classwide peer tutoring were compared to teacher instructional procedures and pretest probes using a group replication design (Barlow, Hayes, & Nelson, 1984). Analysis of group and individual results indicated that (a) both teacher instructional procedures and classwide peer tutoring were effective in increasing spelling performance above pretest levels, (b) peer tutoring produced statistically greater gains relative to the teachers' procedures for both low and high student groups formed on pretest levels, (c) these outcomes were representative of groups, classes, individuals, and years during the project, and (d) participant satisfaction with the program was generally high. A separate analysis of the social importance of treatment outcome revealed differential findings for low and high groups related to pretest levels. Implications of these findings are discussed.